The present invention relates to a stairway, in particular a stairway for use out-of-doors and on rough sloping terrain.
Stairways comprise a series of stairs disposed at intervals along the length of a stairway, which enable a user to travel between two or more levels. The stairway is normally a rigid assembly installed between fixed points on a structure or slope. The construction of the stairway normally entails significant site preparation, time and cost.
In GB 1 273 538, a flight of stairs is described in which a substantially flat metal sheet is bent successively in alternate directions to create a series of steps. A half-landing is provided at the top of a first flight, and a second flight is provided upwardly from that landing. The staircase is intended to be located in the stairwell of a building, and rests at its lower end on the ground floor of the building.
In GB 2 217 359, a staircase is described in which a single-piece concrete casting incorporates pre-stressed wires, which strengthen the staircase and enable load exerted thereon to be transferred to a landing structure.
Both of the above-referenced documents describe staircases suitable for use indoors. However, it is often desired that a stairway for use out-of-doors is able to be constructed on a more temporary basis, preferably such that it can be easily dismantled after use. The structures described above, although suitable for use on a permanent or semi-permanent basis, are less suitable for short-term or temporary use out-of-doors. In particular, if a stairway is required for use on a sloping hillside, for example, or open ground, it is desirable to provide an assembly that is quick and simple to construct, and that requires minimal site preparation. U.S. Pat. No. 3,813,831 describes a knock-down precast staircase, which is suitable for use on sloping hillsides. The staircase comprises individual tread elements and riser elements which are connected together to provide a series of steps. Each step is constructed in turn, and is joined to the next by an interrelationship between the tread element of one step and the riser element of the next. Each riser element includes an intermediate strut, which can support the back edge of the tread element of the next step down.
In EP 0 753 645, a one-piece angled step is described, in which one arm forms a tread element and the other forms a riser element. Hooks or claws are provided on the step for engaging it in the ground. Several such steps may be placed in the ground, one above the other, to provide a stairway-like assembly. Each step may be bonded to the next using a connecting tie.
In the latter two constructions above, only a single step at a time can be secured in the ground, so that the construction of a stairway assembly comprising a series of stairs requires significant site preparation, time and effort.
The present invention aims to facilitate the provision of a stairway out-of-doors, in particular for use on sloping open ground or rough terrain.
According to a first aspect of the present invention, there is provided use of a prefabricated stairway module to form a stairway resting on a sloping surface, the module comprising a first step and a second step, each step having a tread member and a riser member, the stairway module further including plural fixing means spaced along its ascending length for fixing the module to the sloping surface;
wherein:
the first step and the second step are inseparably joined by a bridging member, the bridging member being inclined relative to the tread and riser members so as to conform to the sloping surface, at least some of the fixing means being associated with the bridging member.
According to a second aspect of the present invention there is provided a prefabricated stairway module for resting on a sloping surface, comprising at least first, second and third steps, each step having a tread member and a riser member, the stairway module further including plural fixing means spaced along its ascending length for fixing the module to the sloping surface;
wherein:
the first step and the second step are inseparably joined by a first bridging member and the second step and third steps are inseparably joined by a second bridging member, the first and second bridging members being inclined relative to the tread and riser members, with the first and second bridging members being on the same plane, at least some of the fixing means being associated with at least one of the bridging members.
Preferably, the fixing means includes plural pins, hooks, claws or tethers. The fixing means may be driven through through-holes in the stairway and into the ground on which the stairway lies. Preferably, pins are provided which are driven perpendicularly through through-holes in the module and into the underlying ground. The stairway modules may be further attached by tethers to other supporting structures, to ensure stability of the structure.
The steps in a prefabricated stairway module are preferably rigidly connected to each other. The module may have integrally formed steps. Alternatively, steps in a single module of stairway may be releasably connected to each other, so that the number of steps in the module may be varied according to the length of the slope against which the stairway is to be laid. The steps in a single module may be bonded together by bolts, pins, ties, rivets, hooks, rings, shackles, or other such connectors known in the art.
The module of stairway may be constructed in such dimensions that the depth of the tread member differs from the height of the riser member of the same stair. In this way, the stairway module may be used reversibly, depending on the gradient of the surface against which the stairway is laid.
The steps in a single prefabricated module may be spaced from each other by a bridging member, which may be substantially L-shaped or V-shaped. The configuration of the bridging member will determine the angle at which successive steps in the stairway lie relative to one another. Hence, variations in the gradient of the surface on which the stairway lays can be accommodated by selecting a stairway module wherein the successive steps lie at a suitable angle relative to each other.
The tread member of each step may be curved, again to enable variations in the gradient of the supporting surface to be accommodated. The tread member may incorporate a non-slip surface, such as a patterned, textured, ribbed or perforated surface or an area of mesh.
The tread member of each step in the stairway module may be mounted on a flexible base structure, so that its orientation relative to the slope on which the module is laid can be varied, depending on the gradient of the slope. The flexible base structure may be of moulded plastic, fiberglass, rubber, mesh, woven fibre, or some other suitable flexible material.
The stairway module may be provided with a handrail or guide-rope at one or each side thereof.
In a third aspect, the present invention provides a stairway including at least one stairway module according to the first aspect. The stairway may be constructed using any number and combination of prefabricated modules according to the first aspect. Thus, the stairway may include only modules incorporating rigid bridging members, or only modules incorporating flexible base structures, or a combination of both types of module. Preferably, the stairway modules constituting a multi-modular stairway are joined together by pins or the like, to stabilise and secure the stairway structure.
Preferably, the stairway modules are reusable, and are easily joinable together to form a quickly assemblable and dismantlable stairway construction.
Accessories may be provided for use in conjunction with stairway modules in a stairway according to the present invention. These may include connector plates for securely connecting individual modules in a multi-modular stairway, handrails, guide-ropes, modules of walkway, and non-slip tread surfaces.
Preferably, the stairway modules are suitable for use in the construction of either a temporary or a permanent stairway.
In a fourth aspect of the present invention, there is provided a kit-of-parts for constructing a stairway on an inclined surface, the kit including at least two prefabricated stairway modules according to the first aspect. Preferably, several modules of stairway are provided in various designs and sizes, and with various multiples of stairs. The modules are securable together by suitable connections or fixings.